Treatment of hydrocarbon oils



Jan. 28, 1936. raz,` B, DAY

` TREATMENT OFHYDROCARBON OILS Filed Aug. 25, 1953 Tmcz'onafor Patented4 Jan.Y 28, 1936 .o

UNITED srATEs PATENT OFFICE l,

TREATMENT or HYDaocARBoN oILs Y `Roland B. Day,fCh.icago, `-Ill., assignor to Uni- `versal Oil ProductsfCompanL Chicago, Ill., a

.corporation of Delaware c Applicatio'nnugust 25, l19.23, serialNo. 686,726

2 claims. `(el. 19es55 This invention relatesmore particularly to the treatment ofuhydrocarbon oil distillates of motor fuel Vboilingrange'produc'ed bythecracking "of heavier and less valuable portions of petroleum 5. oils `though similar motor fuel fractions produced from "other sources may alsobe treated such as those producedrin. the straight run `distillation of crudejp'et'roleums or in the 'cracking of tars proc duced inthe primary distillation Aof coals, shales, 1'.\;t0" I In a more specificsense the invention is concerned with aproc'essyvhich may be employed to controllably eliminate they undesirablel constitu- "ents of primary or `untreated motor fuel distil- 17, lates, such constituents being classified generally as thegum-forming and colored compounds and the sulphur-containing -derivatives, the latter imparting a bad odor to the distillates, and causing corrosion of the metal parts of automobile engines eitherbefore or after combustion.

`In one specic embodimentl the invention comprises `the treatment' of hydrocarbon oil distil-` lates, particularly cracked hydrocarbon oil distillates of VVapproximate motor fuel boiling` range at elevated temperatures and pressures with hydrogen chloride and waterlinL the` presence of Vzinc-bearing clays.

Y The present invention is based on the discovery thatcertain types Aof Zinc-bearing clays; particularly those obtained inthe zinc-bearing regions` of Missouri, may be' successfully employed as catalytic materials inV treating cracked distillates with hydrogen chloride and Water for the removal of gum and color-forming and sulfur compounds.`

` Treatments may be conducted either in .vapor phase, mixedphase or substantially liquidphase temperatures varying `from approximately `200 to 600 F. and pressures of from atmospheric to 600 pounds per square inch,` temperatures `and 40 pressures being inter-related so that optimum treating effects are obtained in anygiven case. As a general rule, however,l best results are ob-` tained in mixed phase treatments, that is, treatments in which thereis some liquid and some vapor present in contact with the catalyst and the treating agents. The'exact degree of vaporiza-` tion of the oil under any given set of temperature and-pressure conditions is diirlcult to determine on Vaccount of the presence of the vapors of water and hydrogen chloride which disturb the normal vapor-liquid ratio. However, by determiningthe liquid-vapor ratio'of the stock undergoing treat-` ment in separate laboratory test apparatus and introducing approximate corrections to eliminate the influence of the reagents it would appear that asa general average the oil is about 25% vaporized. For most gasolines and naphthas which boil within the approximate range of 100 `to 500 F.v the bestpressure rangefor treatments is approximately 100 to 200 pounds per square inch and the best temperature range is approximately 350 to 50051?. Obviously, when dealing with gasolines of widely varying chemicalcharacteristics, particularly those from cracking operations upon` different charging oils-,p the exact choice of conditions Will be best based upon experiments in conjunction with tests jupon the products. Howeventhe ranges given are wide enough toinclude the majority of cases.

In regard to the zinc-bearing clays which are preferably used 'as solid contact materials, they vary somewhat in composition, particularly ingrespect to the total zinccontent although the percentage of zinc in the clay as mined is generally of the order of from 20 to 25% by Weight. The exact determination ofthe form of combination of the zinc is attended with the same difculties encountered in determining the other.` components of clays, which can only be approximated in masses of such a complicated` character. The composition and structure of clay mineralsinso-Y far as the' same have been identified is usually determined upon relatively pure clays, and inthe case` of the materials of the present `invention suchoa proximate analysis is attended with still greater difficulty and would be of problematical value. l

It is probable that the zinc is combined partly as silicate and partly as oxide or-hydrated oxide, corresponding generally to the form of combination ofthe other bases commonly present in clays such as aluminum, iron, calcium, magnesium and the alkali metals." The following analysis was ,made on a typical. example of clay which gave good catalytic action.

Analysis of eme-bearing` clay v Per cent SiOz 35.68 Zn 23.40 Al 4.10 Fe 2.67 Undetermined 34.15

`Total 100.00

ial for producing the treating effects according to the process of the invention. To avoid confuV sion between the terms hydrogen chloride and hydrochloric acid, the term hydrogen chloride within the meaning of the presentl specification is hereby stated to designate a dry gas having the chemical formula HC1, whereasv hydrochloric acid designates an aqueous solution ofy this gas inwater.

The presence of water is essential to-thefsuccess of treatmentsconducted according to the present process although it may be added along.,

` with hydrogen chloride in diiferent ways. As examples of alternative modes of procedure for assuring the presence of the required amounts of both hydrogenv chloride and water in the treatments, the following lalternatives are offered though they may not always produce equivalent treating eects:

- 1. Hydrogenchloride and water may be added from separate sources of supply; 2. Hydrogen chloride land steam may be added from different sources of supply; 3. Hydrochloric acid of regulated concentration maybe added. Asa general rule the last named. method is the simplest in practice and usually is preferred overtheV other two. l f f number of cases that a denite degree of vaporization is best in rening treatments of the present character, the reasons for this are not entire--v ly known. The primary yobject of all treatments uponunstable naphthas or gasolines containing unduly high percentages of sulphur and of` gumy forming olens is to reduce the sulfur to'sorne permissible limit and polymerize the' more highly unsaturated oleiins of a diand tricharacter while preserving the mono-olens Vas anti-knock ingredientszcffthe nished product. The selectivity of mixed phase treatments for accomplish'- ing' these ends'is possibly connected insome way with the `time factor and catalytic surface action, but the ini'luencesof these factors are so complicated that their exact analysis lis impractical if not impossible.' -1

` A factor of importance isy the presence of dissolved gases in stocks to be treated such as 'uny stabilized pressure distillate; these gases tending to unduly increase the ratio-of vapor to liquid phase and oiset the desirable treating conditions. '1n some cases itmay be best'to stabilize the gasoline or naphtha prior to its'subjection to the process in order to remove largev amounts of dissolved gases Asuch `as* hydrogen sulfide, methane,` ethane, etc.

The nature'of the reactions which vhave been found to produce the unusually good refining effects upon-cracked gasolines wheny treated according to the invention is diicult of exact determination on'account of the complex character of the hydrocarbon distillates, particularly inl regard to the chemical nature of the gum-'forming compounds and the form of combination of the sulfur whichis present. It may be assumed that the gum-forming compounds consist, to a large' extent, of dland tri-olens of a conjugated" character vsince these compounds are known to readily undergo polymerization. The sulfur comy pounds may be mercaptans, suldes, disulildes,

thioethers, thiophenes, etcetera, besides hydrogen sulde.

' The following 'equations are given to show the possible course of the essential reactions in the formation of readily removable polymers when treating an olefin-'containing distillate with` hy- I `indicated as'the active reagent, but it 'is' to' be 3f) 1 borne in mind thatva ldefinite amount of water whiie it has been` dennitely established in a `uniformly detrimental. to the efficacy rof "the the'tre'atment'in mercaptans yas a result of sec- Ondary, reactions of hydrocarbons with hydropolymerizing cycle so'that "the initial addition' 2,029,256 v n l ldrogen chloride and'water in thepresence of the Intermediate cmo! tine' derivative .Gumlforming olen r E Catalyst l E l y n,v

, y l v l Polymer In. the above equations hydrogen chloride is treatment.; y y. v. ,v

To account for the v.extraordinary eiciencyof vthe process inremoving sulfur :fromAv cracked distillates whichy are refractory fromfthe vstand-- point of ordinary sulfuric ,acid treatments, two types of reactions may'lbe'consideredfthe rst involving polymerization' of sulfurc'ompounds' along with thehighlyunSaturated hydrocarbonsrv so that the sulfur'l appearsin' the heavy polymers and, second, those involvinga preliminary com bination of organic sulfurlwith a clay base, par-l ticularly zinc; A to .formo suldes'wnich are laterj decomposed 'by hydrochloric acidfto evolve hy-l drogen 'sulfide as` a gas. "'.These'reactions are merely 'assumed andtheir proof would involve ai.

series of difficult 'analyses' which, ifl not4 impos; 4J

sible, wouldadd little value to the present specication. Some evidence is at hand to` show that' combined sulfur inhigh sulfur oils appears after gen sulde originally formedL However, 'with suitableprecautions which'will be developed in connection 'with adescription of an' operation,

this tendencytowa'rd mercaptan'formation can; be minimized.'y 'l y 'c f Usuallyk only small amounts of hydrogen chloride are requiredv in the treatments." According to the characteristic equationsgivenfabove itv is completely regenerated at'the end 'of the y of some denite amount would suii'rice." However,

certain small losses are unavoidable 'o naccount.` of its volatility'which results inits being'fcarried forward toi the fractionating and condensing ce equipment of 4the treating apparatusQ Such losses may be counterbalanced by' the addition' of equivalent amounts of acid,feitherfromv outsidesources or recovered by absorption fromthe distillateV receiver gases.

y ,v v7o The process may be conducted -in'any suitable ktypeof apparatus and Fig. 1 showsy diagrammati-i *i cally the essential featuresof af plant layout 1 which can be,used...kv .y 1@ i Distillates to be treated-may beintroduced to` 75 t t u 2,029,256 the plant through line I, containing control valve 2, and vpumped by pump 3 through line 4, con- `taining control rvalve 5, into and through heating s element 6 disposed to ,receive heat from furnace 1. t After being brought to a suitable temperature for treatment the heated products may be discharged through line 8containing controlvalve ydischarging by `way of line I9, containing control valve 2U, into'line I -,where it mixes with .the heated oils. VAs stated before, hydrogenchloride andwater or steam may be separately intro- ,duced althoughvmeans for this are not shown'in the drawing. h s

The acid, `water and oil vpass underselected `temperature and pressure conditions within the ranges previouslyY mentioned through valve II and enter pressure treater I2 which contains a mass of zinc-bearing clay particles I3 dividing the interior of the treater into upper and lower spaces I4 and I5, respectively. During the pas` sage of the oil and acid through thecontact mass,

degumming andfdesulfurizing reactions are effected and the products of Vthe treatment pass through line 2l, containing control valve 22, to fractionator 23, valve 22 being so manipulated in conjunction with valves subsequent `to the fractionator that the pressure'obtaining on the pressure treater is substantially reduced in the fractionator which may operate, for example, at 'pressures of from 50 to 100 pounds per square inch. I Y

'Ihe plant showninthe drawing is designed' for upward flow of 'y oil and reagents over the clay particles but downiiow treatments may also be used if greater` benets are obtained thereby. Higher boiling fractions than are desired in the Afinished gasoline appear in theV fractionator as heavy polymer refluxes and comprise high boil` ing andsubstantially unaffected hydrocarbonfractions which may have been'present in the raw naphtha if such was treated, and also polymers of oleilns.

such a series being vented beforefurther contact isbrought about, thus reducing the tendency to metal sulfide formation with corresponding depreciation in the value of 'the contact materials.

By ventingthe fixed gases and thus removing the majority of hydrogen sulfide the formation of mercaptans may be reduced to a practical minimum so that the desulfurization is more effective.

Any hydrogen chloride which may be lost when the hydrogensulfide and other low boiling hydrocarbons or fixed gases are released may be counterbalanced by furtheradditions prior to the suc- .ceeding pressure 'treaten The vented gases may be passed through auxiliary beds of granulated metals and the chlorides and suldes recovered if desired, or any. other method of recovering the gen sulfide may be employed.

acid for further use or of getting rid ofthe hydro- The reluxes from fractionator 23 maybe removed through line .24, containing control valve 25 and disposed of in'any suitable manner. In case these reuxes are' of fairly low sulfur content Some sulfur may appearin the polymers and otherwise suitable, they may be used as recycle stock inthe cracking plant which produced the naphtha or gasoline to be treated.

The vapors and xed gases from the fraction- Vator `may be conducted through vaporl line 26,

containing control valve 21, and be cooled during passage through condenser 28, the cooled gases and condensed gasoline passing through rundown line 29, containing control valve 30, to receiver and separator 3l whichhas line 32, containing control valve 33 forthe controlled release of xed gases, a` draw line 3L containingcontrol valve 35, for the removal of the nished gasoline and a bottom draw line V36, containingcontrol Vvalve 31 for Vremoval of water or aqueous solution which may accumulate inl the receiver.

Obviously, to reduce corrosion troubles the por-V tions of the plant which are subjected to contact with hydrochloric acid maybe constructed of suitable acid-resistingmaterials.

The following examples of *results obtained in commercial operations according to the present process are given to show its commercial value:

Example 1 The stock treated to produce a finished gasoline was a `cracked gasoline produced from a` West Y 'Ijexas lresiduum. This distillate was passed through a stationary body of zinc-bearing clay consisting of particles of from approximately 6 to 10 Vmesh at atemperature of approximately 450 F. and a pressure of 150 pounds per square inch. Water and hydrogen chloride were used at a rate corresponding to one pound per barrel of '40% hydrochloric acid. The following table shows the properties of the charging oil andthe properties of the finished gasoline along with Ythe losses encountered:

End pointed gasoline Properties i Untreated Treated Gravity A. P. I 55. 5 58.0 Color, Saybolt Yellow. i 30 plus Color stability l 24 Gum, Mg.ll00 cc. (copper dish) 942 t 48 Sulfur, percent 22 0.17 Doctor test `liositve. Negative. Polymerization loss, percent 3. 2 Octane number 73 (on 400 73 F. E. P.)

Distillatlon I. B. P. "F 112 106 percent over at 145 138 1o `134 16o `195 196 226 W8 254 256 283 E2 97. 0 98. 0 1. 0 l. 0 Percent loss 2. 0 1. 0

l Equivalent to 2 hours noon June slmlight.

Example 2 A Nl y tillate and lthe endpoint distillate 'producible therefro'nrby simple distillation without chemical treatmerit The 'thirdcolumn' showsthe properties' of the product" lfrom the .treatnient'which correspondsto the untreated end point distillate ofcolumnNmz:

End-pointdslillate V Pressure l Properties distillate' y U'n I treated Treated Gravity A.P.I` l 54.5 55.7

" Yellow. 30 plus.

275 s 12 @0 0 je iy AColor after 4-hou`rso dation Y 20.

Sulfur, percenty 1 .03 Mercaptan sulfur, perccnt 012 O Oxygen bomb stability, minimum ,'1230 Polymerization loss, .percent ofv clmrge 2.7 Octane number. 70 -70 114 l 112 147 149 16S A'167 202 #205` l233 235 y' 260 A263 308 306 326 326, r364' 346 l-37'7' 367 393 385 415 Y v407 A98.0V 96.0 -1.0 1.0 Percent loss. 1.0 3.0

l Equivalent to 2 hours noon June sunlight.

` to'2o0pounds per square inch.

l t will be seen from vthe data presented in the two examples that anisl'iedn gasoline was'producedwith onlymoderate losses of the' order of from 2 to 3%. v'The color and color stability Were brought 'uptogstandarmthe guins were markedly the octane number was unaected. n -I claimas'rny invention: f

reduced along with' a bomb stability increase; and

1. A process forfrefning `'liyd'roo'arb'on oils of' approximately motor fuelboiling range Ywhich comprises treating the-oilfata temperaturebetween 200 andfr600 'wthjladded' aqueous ,Zinc-Bearing'layq A f y-.2, A"process-,f or` refining hydrocarbon oilsl of ACil y hydrogenchloriden thevpresenee'ot" a natural u approximatelyjfmotor fuel lbfoilingrzrange Willich -V comprises treating the oilrwith `added'aqu'eous hydrogen chloride'in the presence of alnatural zinc-bearing clay at a temperature of lfrom 350 F,Ato 500 F. and under apressure of from 100 2Q 'ROLAND Bv. DAY;A 

